The new episode tackles themes of police brutality and discrimination via its 'Citadel of Ricks' concept

In the latest episode of Rick and Morty, known alternately as ‘The Ricklantis Mixup’ and ‘Tales From The Citadel’, the fractures in a divided and unbalanced society grate against one other unbearably. The upshot – a brutal mirroring of America’s woes – has earned the show its highest-ever rated episode, with an average score of 9.9/10 on IMDb.

‘The Ricklantis Mixup’ ignores our own Rick & Morty (from dimension C-137), instead heading to The Citadel of Ricks – which was torn apart by Rick C-137’s catastrophic attack in season 3, episode 1. Here, Mortys from innumerate dimensions play second-class citizens who are constantly under the boot of their corresponding Ricks.

As well as the institutionalised discrimination and police brutality that this scenario entails, the 22-minute episode manages to pack in populist politics, adolescent directionlessness (via Stand By Me) and dissatisfaction, crafting an improbably searing critique of real-world America, and reintroducing a formidable villain – Evil Morty – to set-up season 3’s endgame.

It was a classic Rick & Morty episode, containing a beautiful mix of the show’s strongpoints. Wackiness, parody, science-fiction, tragedy, humour – they were all here in spades. In addition to rating the episode an unprecedented 9.8/10, fans have also lavished praise on the writing and voice acting – because 98% of this episode was voiced by Justin Roiland, who played dozens of variations of just two characters.

Kumail Nanjiani, star of The Big Sick, was among the most vocal proponents of the episode:

Just watched last night's Rick & Morty with my mouth open. Nothing will ever be the same. This is not hyperbole.